SKGF_Advisory_Consider a Prosecution History Disclaimer for Every Continuation Application_2007


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SKGF_Advisory_Consider a Prosecution History Disclaimer for Every Continuation Application_2007

  1. 1. Consider a Prosecution History Disclaimer for Every Continuation Application Michael V. Messinger & Jon E. Wright July 2007
  2. 2. Consider a Prosecution History Disclaimer for Every Continuation Application Michael V. Messinger and Jon E. Wright Patent owners and practitioners should consider modifying their continuation practice in light of a recent case from the Federal Circuit. In Hakim v. Canon Avent Group, the court appeared to lay down strict requirements for practitioners using continuation applications to broaden unnecessarily narrow claims and clarify unnecessary estoppels created during prosecution of parent applications. In Hakim, the court relied on statements made during prosecution of a parent application to narrowly construe a claim term that was explicitly broadened in the child application. The court ruled that the applicant's efforts to disclaim the perceived estoppel were insufficient. In a case involving quot;sippy-cupquot; valves, patent owner Hakim argued around asserted prior art references by pointing to two separate mechanisms used to prevent leakage. The first mechanism was a flexible valve material having a quot;slitquot; therein that responds to suction. The second mechanism was a quot;blocking elementquot; against which the quot;slitquot; rested when in a relaxed position. Hakim stated that quot;[n]one of the references cited in the Office Action … teach or suggest such a no-spill mechanism having a slit sitting against a blocking element such as recited in all of the pending claims.quot; The Examiner allowed the pending claims. Believing that the term quot;slitquot; was too narrow, Hakim filed a continued prosecution application, or a CPA. The CPA was accompanied by an attorney letter stating that Hakim was broadening claims 1 and 2, and an amendment changing quot;slitquot; to quot;opening.quot; The continuation claims were allowed with no further comment or rejection by the examiner, and issued in U.S. Patent No. 6,321,931 (quot;the '931 patentquot;). Hakim sued Cannon Avent Group (quot;Aventquot;) alleging that its sippy-cup valves infringed Hakim's '931 patent. The Avent valves had a hole in the flexible valve material, instead of a slit. A key issue became how to construe the term quot;openingquot; in the '931 patent. Despite the Hakim's attempt to broaden the claims in the continuation application, the district court narrowly construed the '931 claims to a sealing mechanism that includes a flexible valve material or diaphragm having a slit. The district court stated: quot;Because Hakim did not retract any of his arguments distinguishing the prior art, he is held to the restrictive claim construction he argued during prosecution of the patent.quot; The court thus ruled on summary judgment that Avent's devices did not infringe. On appeal to the Federal Circuit, Hakim argued that the district court improperly relied on the arguments he made during prosecution of the abandoned parent application. According to Hakim, he avoided any perceived estoppels that may have crept into his claims by re-filing his application with the broader claims, and explicitly flagging the change to assist the examiner.
  3. 3. Avent, on the other hand, argued that the totality of the prosecution history nonetheless limits Hakim to the embodiment with the slit. Avent stressed that quot;when Hakim wrote to the examiner that he was broadening the claims, he did not specifically point out that he no longer intended to be limited to the specific mechanism that he had previously argued was the distinguishing feature of his invention.quot; (Slip op. at 5-6.) In a unanimous decision, the Federal Circuit panel affirmed the district court ruling. The court acknowledged that Hakim quot;had the right to refile the application and attempt to broaden the claims.quot; (Slip op. at 6.) However, the court also stressed the well known doctrine of prosecution history estoppel, noting that quot;an applicant cannot recapture claim scope that was surrendered or disclaimed.quot; Relying on the public notice function of the patent and prosecution history, the court stated: quot;Although a disclaimer made during prosecution can be rescinded, permitting recapture of the disclaimed scope, the prosecution history must be sufficiently clear to inform the examiner that the previous disclaimer, and the prior art that it was made to avoid, may need to be revisited.quot; It is well settled that the prosecution history of related cases is relevant intrinsic evidence that may be considered during claim construction. With this ruling, however, the Federal Circuit made it clear that simply filing a continuation application with broader claims is not sufficient to overcome or disclaim arguments made over the narrower claims during prosecution of the parent. This is true even where the applicant explicitly advises the examiner that the continuation claims are broader than those in the parent. To pursue broader claims than argued previously, an applicant may now have to make an explicit disclaimer by informing the examiner of pertinent art cited in the parent application, and arguments made to avoid it. In view of Hakim, the authors suggest patent owners and practitioners reconsider their current continuation application practice. This is especially true where continuations are filed to broaden unnecessarily narrow claims or to clarify unnecessary estoppels that may have crept in during prosecution of the parent. One solution may be to include a blanket disclaimer such as the following: The claims in the instant application are different than those of the parent application or other related applications. The Applicant therefore rescinds any disclaimer of claim scope made in the parent application or any predecessor application in relation to the instant application. The Examiner is therefore advised that any such previous disclaimer and the cited references that it was made to avoid, may need to be revisited. Further, the Examiner is also reminded that any disclaimer made in the instant application should not be read into or against the parent application. In sum, any continuation application should be evaluated with the lessons of Hakim in mind. Whether using a blanket disclaimer, or something more specific, applicants should explicitly and directly disclaim previous statements that could unnecessarily carry forward and contaminate continuation claims. Existing patents issued from continuation applications may also need to be reviewed with care where continuation disclaimers are absent.
  4. 4. Such continuation disclaimers are a new animal. Time will tell whether they will be effective. Hakim, if read broadly, may be a new hurdle to filing successive continuations in U.S. patent practice. On the other hand, practioners may be able to harness continuation disclaimers to keep the door open for continuation practice and clearly overcome prior estoppels. This article reflects the present thoughts of the authors, and should not be attributed to any of Sterne, Kessler, Goldstein & Fox P.L.L.C. former, current, or future clients. The content is for purposes of discussion and should not be considered legal advice. Copyright 2007 Sterne Kessler.
  5. 5. Sterne, Kessler, Goldstein & Fox P.L.L.C. 1100 New York Avenue, NW Washington, DC 20005